The purpose of this research is twofold: 1) to apply a user-centred approach to examine the usability and acceptability of an on-body ergonomic aid called the Personal Lift Assistive Device (PLAD) in a variety of industrial work environments and 2) to utilize subjective user acceptability data on discomfort, pain and overall PLAD assessment by participants to identify design features that need improvement in the next PLAD iteration. Case studies took place in four different industrial work environments: two distribution centre environments, one retail store environment and one automotive assembly plant environment. These environments were selected to represent different industrial work environments. In total, 20 industrial workers were selected to wear the PLAD and provide their feedback. Results were obtained using subjective questionnaires through verbal and written comments as well as through direct observation of the participants. Three major design changes occurred to the original PLAD iteration tested at the first industrial location. These included: 1) using different stiffness levels of springs for different sizes of individuals in an attempt to decrease discomfort and optimize the effectiveness of the PLAD, 2) an increase in pelvic spacer size and surface area contacting the user’s body to reduce discomfort and 3) modification to the shoulder harness including; shape, dimensions and amount of cushioning to reduce discomfort. Currently, three major design changes were identified and still need to be addressed. These include: 1) reduction of thermal discomfort caused by wearing the PLAD, 2) validation of selecting the appropriate spring stiffness for small, medium and large users of the PLAD (male and female) under various working postures and 3) simplification of the donning and doffing process. Additionally, a simple PLAD spring stiffness sizing chart was created to aid potential manufacturers of the PLAD to select the appropriate spring stiffness for various users of the PLAD. This sizing chart was designed to maintain an average lumbar moment reduction of 15%, while taking discomfort of the shoulders caused by the spring stiffness and overall cost into consideration. / Thesis (Master, Kinesiology & Health Studies) -- Queen's University, 2011-09-28 09:03:01.463